Neurosurgical Applications of Magnetic Resonance Diffusion Tensor Imaging

Magnetic Resonance (MR) Diffusion Tensor Imaging (DTI) is a rapidly evolving technology that enables the visualization of neural fiber bundles, or white matter (WM) tracts. There are numerous neurosurgical applications for MR DTI including: (1) Tumor grading and staging; (2) Pre-surgical planning (determination of resectability, determination of surgical approach, identification of WM tracts at risk); (3) Intraoperative navigation (tumor resection that spares WM damage, epilepsy resection that spares WM damage, accurate location of deep brain stimulation structures); (4) Post-operative assessment and monitoring (identification of WM damage, identification of tumor recurrence). Limitations of MR DTI include difficulty tracking small and crossing WM tracts, lack of standardized data acquisition and post-processing techniques, and practical equipment, software, and timing considerations. Overall, MR DTI is a useful tool for planning, performing, and following neurosurgical procedures, and has the potential to significantly improve patient care. Technological improvements and increased familiarity with DTI among clinicians are next steps

Carotid artery dissections from TCAR as reported by the Food and Drug Administration

BACKGROUND: Transcarotid artery revascularization (TCAR) is hybrid procedure that allows carotid stenting using direct surgical access of the carotid artery to restore blood flow through the carotid artery. It has shown the lowest perioperative stroke rate when compared with any prospective trial of transfemoral carotid artery stenting. However, intraoperative injuries related to the procedure and its management are not well characterized. We anticipate that this analysis will add qualitative insight in further characterizing adverse outcomes of this novel technology. METHODS: The FDA maintains a database called the MAUDE (Manufacturer and User Facility Device Experience) for surveillance of all medical devices approved for use. This database was queried for all cases associated with Silk Road Medical’s ENROUTE Transcarotid Neuroprotection System from September 2016 to October 2020.. Case narratives related to patient injuries were individually analyzed to determine type (carotid artery dissection) and time of injury (intraoperative, recovery, post-discharge follow- up). Carotid artery dissection (CD) reporting was further analyzed for associated procedural event at the time of injury, number of access attempts to CD repair, and type of CD repair. RESUTS: Of the 115 unique incidents in the database, there were 58 CDs. Most were identified intraoperatively (n=55), while 3 were incidentally identified postoperatively. Overall, sheath placement was the most common procedural event attributed to CD (n=34). There was adequate narrative information about CD repair in 54 patients where 52 of them were performed intraoperatively. There were total of 28 endovascular repair and 24 open surgical repairs of CDs from TCAR procedure. There was no significant difference in rate of endovascular and open surgical repair of CDs that did not need additional access attempts. However, rate of open surgical repair was significantly higher in CDs with persistent failure to engage the true lumen in 2 or more additional access attempts. Total of 4 strokes were associated with CD. Two occurred during recovery from TCAR admission where one was not intervened per physician’s discretion despite evidence of dissection during the procedure. The other was associated with a fall from a hypotensive event 7 hours after an endovascular CD repair. One incident of stroke occurred intraoperatively during a conversion to CEA as a result of CD. One incident of stroke occurred 4 days after TCAR procedure in which a CD was identified during the stroke evaluation Conclusion: Carotid artery dissection is the most common injury related to TCAR as reported on MAUDE database. Most common procedural event associated CD was sheath placement. Rate of open surgical repair was significantly higher than endovascular repair in dissections with persistent failure to engage true lumen despite additional access attempts. This should add to qualitative insight among vascular surgery community regarding intraoperative management of carotid artery dissections from a TCAR procedure.https://scholarscompass.vcu.edu/gradposters/1144/thumbnail.jp

Replacing Adjunctive Medications for Treatment-Resistant Depression Using Repetitive Transcranial Magnetic Stimulation: Case Report

Repetitive transcranial magnetic stimulation (rTMS) is an effective treatment for depression. As the left prefrontal cortex activity is linked to depression, rTMS induces blood flow in the left dorsolateral prefrontal cortex (dlPFC). Long acting psychostimulants are sometimes prescribed as an adjunctive antidepressant treatment throughout rTMS therapy. We used rTMS to treat resistant depression in a middle-aged male patient over a twelve month period where a psychostimulant medication was also discontinued. He had been consistently taking duloxetine 60 mg BID, clonazepam 0.5 mg BID, and dextroamphetamine-amphetamine extended release 30 mg once daily prior to the onset of rTMS treatment. The patient achieved depression remission through the course of 39 high-frequency left dlPFC rTMS treatments. The treatment was repeated for a course of 11 treatments in 2020 and 17 treatments in 2021 for symptom recurrences while the stimulant was discontinued. We assessed progress using Quick Inventory of Depressive Symptomatology (QIDS) and we took blood pressure measurements before each session of rTMS. After tapering DX-AM XR from 30 mg to 10 mg and then discontinuing it, QIDS increased slightly to 7 and then dropped to 0 after re-treatment. A second recurrence was treated with rTMS and adjunctive liothyronine 25 mcg once daily. QIDS score dropped from 20 to 10. It is noteworthy that there appeared to be a gradual decline in the patient’s blood pressures from the first day of treatment to the last. Results indicate that interval rTMS may be used to replace an adjunctive psychostimulant and lower blood pressure

Educational Programs and Adaptability: A Systems Approach to Creating Adaptable Educational Programs

The IUSM Scholarly Concentrations Program is an optional four-year longitudinal program that allows students to explore interests outside the core medical curriculum. In two years, 17 concentrations were developed statewide and more than 220 students enrolled. As a part of developing a sustainable educational program, a Plan-Do-Check-Act improvement cycle is being used. This workshop will feature examples of the use of the Plan-Do-Check-Act improvement cycle during the launch and pilot a large, novel educational program that is “good enough” and builds toward sustainability and excellence while responding to large-scale systematic changes. Participants in the workshop will apply these principles to their own educational programs

D.I.R.E.C.T. Pathway (Delayed Imaging to Reduce Excessive Computed Tomography) for the Evaluation of Patients with Suspected Renal Colic

Flank pain and the diagnosis of acute renal colic is one of the most common and costly evaluations performed in the emergency department (ED) in the United States. The gold standard for diagnostic imaging of patients who present with flank pain remains non-contrast computed tomography (CT) due to its superior sensitivity and specificity for the identification of urolithiasis when compared to other imaging modalities. Due to concerns regarding radiation exposure, cost, and incidental findings, the relative benefits of alternative imaging modalities for the assessment of suspected renal colic have been evaluated. Ultrasound (US) in particular has been shown to be a safe alternative approach in this clinical scenario. Ultrasound, however, has limitations in defining specific anatomic and stone information needed by urologists to guide clinical management. An US-first, delayed CT approach for the evaluation of patients with suspected renal colic is both feasible and safe. ¾ of enrolled patients received US alone with no missed alternative diagnoses or complications. Nearly 40% of subjects definitively passed a stone and only 10% required surgical intervention. Avoiding upfront CT imaging should be strongly considered in this patient population. The need for confirmatory imaging or clinical follow-up to ensure stone passage remains a question that will require further study and additional long-term data

Intraoperative PTH Monitoring in Normohormonal Primary Hyperparathyroidism

Background: A subset of patients with primary hyperparathyroidism present with inappropriately normal PTH levels despite elevated serum calcium, called normohormonal primary hyperparathyroidism (NHPHP). This disease variant presents a clinical dilemma regarding intraoperative parathyroid hormone (IOPTH) monitoring during parathyroidectomy when using the standard criteria of a ≥ 50% reduction in IOPTH from baseline to determine surgical success. This study aimed to determine what percent reduction in post-excision IOPTH from baseline in NHPHP patients would yield a high cure rate similar to that of classic primary hyperparathyroidism. Methods: This was a single surgeon, single institution retrospective cohort study of patients that underwent parathyroidectomy between July 2013 and February 2020. Demographic, preoperative, intraoperative, and postoperative metrics were collected. Patients with NHPHP were compared to those with classic primary hyperparathyroidism. Results: 496 patients were included in the study. 66 (13.3%) were of the normohormonal variant based on preoperative intact PTH levels and 28 (5.6%) based on baseline IOPTH levels. The cure rates in the normohormonal groups were not significantly different from their classic counterparts: 98.4% and 100.0% vs 97.1% and 97.1%, p = 1.000. The median percent decline in post-excision IOPTH from baseline that achieved cure in the normohormonal groups were 82.8% and 80.4% compared to their respective controls of 87.3% and 87.1%, p = 0.017 and p=0.001. Conclusion: A ≥ 75% decline in 15-minute post-excision IOPTH level from baseline can be used as a more stringent criterion for achieving high rates of cure in patients with NHPHP that undergo parathyroidectomy